Method of making reinforced multiply paper



April 7, 1959 A J. D'A. CLARK 2,881,072

METHOD oF MAKING REINFORCED MULTIPLY PAPER v Filed Jan. 17, 195e CD v OQ O la TaHAl/dz'fzbnal asses andryere on after Presses) IN VEN TOR.

Jamas eL/, Clark @W5/Include Cmpg'rzy y METHOD oF MAKING REINFORCEDMULTIPLY PAPER James dA. Clark, Longview, Wash., assignor to FihrofeltCorporation, Chicago, Ill., a corporation of Illinois ApplicationJanuary 17, 1956, Serial No. 559,589 Claims. (Cl. 92-21) Thisinventirin` relates to the manufacture of' papers and webs reinforcedwith fibers of substantial lengths and f it relates more particularly toa thin laminate in the form of a paper fabricated of conventionalcellulose pulp fibers` having a lamina of fibers of reinforcing lengthsintegrated therewith to impart strength properties and other desirablecharacteristics to the structure and it relates further to a method forthe manufacture of same.

In the present manufacture of paper wherein use is made of a furnish ofpulp fibers thinly dispersed in an aqueous medium for application by wayof a headbox upon a continuous moving wire of a Fourdrinier machine forthe separation of the pulp fibers on the surface of the wire to form aweb, it is'difiicult to incorporate and uniformly to distribute. fibersof substantial lengths, such for example as fibers having lengths inexcess of about Y, invention;

`ice

of fibers as between the pulp fibers and the fibers ofreinforcingflengths to produce structures for use in a number ofdifferent types of applications.

These and other objects and advantages of this invention willhereinafter appear and for purposes of illustration, but not oflimitation, embodiments of the invention are shown in the accompanyingdrawing in which- Figure l is a schematic diagram showing thearrangement of elements for use in the practice of this invention;

Figure 2 is a schematic diagram showing a different arrangement ofelements for use in the practice of this Figure 3 is `an enlargedsectional elevational view through a product which isA prepared by themachine illustrated inFigures 1 and 2;

Figure 4 is an enlarged sectional elevational view of a modification ina product which embodies the features more layers of fibers formed, asby conventional procl: inch for deposition alone 'or incombination withthe pulp fibersv to producea paper having increased tear strength, burststrength and tensile strength.' Such strength properties are desirablein a paper intended to be used for bags, wrapping or sheets for themanufacture of case liner papers and the like in which high strength,wet strength and the like propertiesA are important.

To the present, reinforcement with fibers has been limited either to theuse of continuous filaments or threads which are fed in side by sideparallel relation into the furnish as it is fiowed on the wire fordisposing the continuous threads or filaments in the describedrelationship within the web that is formed or else use has been made ofa woven reticulated web which can be, in various ways, included as apart of the sheet of paper during its manufacture. When use is made ofsuch endless filaments or threads, reinforcement is limited to thelongitudinal direction without increasing the strength of the paper inthe crosswise direction and the cost of the endless yarns, strands orthreads or thecost of the woven, reticulated web is excessive bycomparison with the rest of the materials making up the paper andapplication as a part of the paper becomes difficult with the resultthat the paper that is formed is expensive and limited in application tovery speciall uses.

It is an object of this invention to produce and to provide a method forproducing a paper in which use is made of fibers of substantial lengthsfor reinforcement, in which the reinforcing fibers are uniformlydistributed in haphazard arrangement in the paper to impart strength inall direction, in which the reinforcing fibers of substantial lengthsare formed of a material which differs from the pulp fibers comprisingthe main body of the paper, in which the fibers of' reinforcing lengthscan be treated in advance to impart new and improved properties to thefibrous structure into which it is incorporated, in which` the fibers ofreinforcing lengths are applied without marked increase in the cost ofthe process and without marked increase in the cost ofthe product overand above the differences in the cost of raw materials, and in whichconsiderable fiexibility is-,available in the arrangement esses, asrepresented by the wet process of a Fourdriniermachine, and one or morelayers of dry fibers formed by an air deposition process of the typedescribed in my copending applications Ser. No. 61,674, filed November23, 1948, and Ser. No. 464,102 and now Patent No. 2,749,576, filedOctober 22, 1954, and Patents No. 2,702,-

005, issued October 1l, 1955, and No. 2,698,271, issued- December 28,1954. As describedin the aforementioned applications and patents, dryfibers are suspended in an air stream moving under positive pressureover the inner surface of a separating wall having foramens thereindimensioned to enable passage of substantially separated fibers wherebya shower-head effect is developed to cause substantially equal volumesof air and fibers to pass through the openings in the separating wall toa collecting wall which is spaced a short distance below the sepalethers and esters and' regenerated cellulose and proteinv rating wall.The collecting zone, usually in the form of an endless screen travelingcontinuously in one direction beneath the separating wall, separates outthe fibers on the surface thereof as the stream of air continues throughthe screen to form a web on the surface in which the fibers aresubstantially uniformly distributed in a heterogeneous arrangement'.

The system described can be used effectively with fibers of substantiallengths to produce a web ranging from al Very thin layer of fibers to alayer of substantial thickness, depending upon the capacity of the fiberdepositing head, the linear speed of the separating screen and thenumber of heads which are employed for thev deposition of fibers. inaddition to the ability to form a very uniform, randomly oriented andwell dispsersed thin webl of interfelted fibers, the system can bepracticed for the deposition yof various types of fibers including glassfibers which are desirable because of their high strength, inertness,electrical resistance, low thermal conductivity and resistance todeterioration, or synthetic organic fibers, such as the polyesters(Daeron), polyamides (nylon), polytetrafiuoroethylenes (Teflon),polyvinyl chloride (Vinyon), polyvinylidene copolymers (saran),cellulose fibers (rayon), and natural fibers such as flax, hemp, silk,cotton, wool and the like, or metallic fibers.

It is conceivable that the process described in the afore-4 mentionedcopending applications and patents could be employed toform a non-wovenstructure of such fibers of reinforcing lengths for use in substitutionfor the expensive woven, reticulated structures heretofore employed asan interlayer with the cellulose pulp fibers in the manufacture of highstrength papers. However, the web of the type described for separate usemust have adequate self-sufficiency to enable the web to be handled informlng, to enable the web to be rolled up into a compact package fortransfer to different stations and to enable the web to be unrolled atthe station of use for application as an interlayer or lamina in thefibrous structure that is formed. Even when the fibers of reinforcinglengths lare formed to substantial thickness, the desired degree ofself-sufficiency is incapable of being developed. As a result, itbecomes necessary -to make use of substantial amounts of binding agentwith the result that the web is increased in cost and unless it ishydrophilic, the binderpresent may tend to interfere with the ability ofthe pulp fibers to become integrated with the bonded web of long fibersincorporated therewith. In addition, the use of a thin web of fibers ofreinforcing lengths is complicated by the fact that speeds aremaintained in operation for the manufacture of paper from pulp and thatsuch operation at high speeds is continuous. This will be appreciatedwhen it is realized that papers are generally fabricated on machines atspeeds of upwards of 500 feet per minute in a continuous operation sothat the incorporation to include a web presents a real problem when thelength of the web is limited in the roll.

Thus, another object of this invention is to produce a reinforced highstrength paper of the type described in an economical and efficientmanner with a machine operating at high speed on a continuous processand it is a related object to provide a method whereby such webs ofreinforcing fibers can be supplied as endless webs coordinated inoperation with the paper making machine for coordination therewith inthe manufacture of a fiber reinforced paper in which the paper isreinforced in all directions and in which the web is supplied at a speedequivalent to that used in the manufacture of paper and wherein the webis supplied continuously for incorporation with the paper as it is beingformed.

Another object is to provide means for the incorporation of long fibersin uniform distribution and haphazard arrangement in a paper web withoutthe expense and limitations imposed by the use of a woven or bondedstructure preformed of the reinforcing fibers.

A further object is to produce an improved paper formed of thecombination of the cellulose pulp fibers and a non-woven, open meshfabric of fibers of reinforcing lengths wherein the fibers in theproduct vare interfelted one with the others to resist delamination andto avoid the necessity for application of excessive amounts of bondingagents for securing the bers one to the other in the structure.

With reference now to the drawing, illustration will be made of thepractice of the concepts of the invention by the combination of a wetprocess and a dry process for the deposition of fibers in themanufacture of a paper product of the type heretofore produced by aconventional multi-cylinder board machine or the like but in which theproduct contains a uniform distribution of fibers of reinforcing lengthsthroughout a portion parallel with the flat faces of the formed paper orboard.

In the modification illustrated in Figure l of the drawing, a highstrength paper is formed of a plurality of webs as represented by thenumerals 12 and 14 brought together in the form of lamina with a web 16of fibers of reinforcing lengths in between. For this purpose, use ismade of a plurality of cylinder vats as represented by the numerals 18and 20, of a conventional board machine having cylinders 22 mounted forrotational movement in the wet slurry 24 in the vats for the depositionof fibers on the periphery thereof to form individual webs. Passing insuccessive fashion over each of the cylinders 22 and substantially incontacting relation therewith is a pick-up felt 26 in the form of anendless woven blanket A which operates about rollers 2B, 30, 32, 34, 36,38 and 40, the last four of which are adjustable tensioning and aligningrollers. As the felt 26 passes over each cylinder 22, the web formed onthe periphery is picked off to form additional lamina on the undersideof the felt.

The web 16 of fibers of reinforcing lengths is incorporated as a laminaafter the felt 26 has picked up one or more of the fibrous layers fromthe cylinders 22 to provide a corresponding number of wet layers as aweb 12 on the underside of the felt. Unlike the web of fibers previouslyapplied for incorporation to form the composite fibrous structure, thefibers of reinforcing lengths are provided in the form of a dry web 16which is separately formed, as by the process previously described, at arate corresponding to that for the formationv of the wet web so that theweb of dry fibers of reinforcing lengths may be couched for transferonto the wet lamina or web 12 of the pulp fibers previously formed onthe underside of the felt.

For this purpose, the fibers of reinforcing lengths areV fed by suitablemeans into the fiber depositing head or heads 42, in the form of acylindrical housing and either mechanical scrabbler means, as describedin application Ser. No. 61,674, or air scrabbler means, as described inPatent No. 2,702,005, are employed to swirl the'fibers in an air streamabout the interior of the cylindrical housing to create a shower-headeffect which causes uniform volumes of air and fibers to pass throughthe openings in the foraminous separating wall of the housing to thecollecting wall, which in this instance is represented by an endlessscreen 44 operating about rollers 46, 48 and 50. The air is drawnthrough the wire or screen into a suitable suction chamber.52 locatedbeyond the screen or wire in the fiber depositionzone and the fibers areseparated from the air stream .for deposition onto the surface of thewire toform a thin web 16 in which the fibers lie essentially in ahaphazard arrangement. One

such depositing head may be employed or more than onel may be employedas illustrated to deposit one layer of fibers onto the other layerpreviously deposited with the fibers of the latter drawn into the layerof the fibers previously deposited to provide an interfelted web whichis essentially incapable of delamination.

Instead of depositing the same fiber from each of the heads, one type offiber can be deposited from one head for interfelting with fibers of adifferent composition or length from the other head or heads. By suchmeans, a combination of glass fibers and cellulosefibers, or glassfibers, and a thermoplastic resinous heat s oftenable fiber may bedeposited or elseglass fibers of substantial lengths up to 2-3 inchesmay be deposited from one head for combination with fibers -of ultrafine dimensions and of shorter lengths from the other heads and thelike.

The web 16 of dry fibers of reinforcing lengths formed on the wire orscreen 44 is couchedonto the lamina 12 of wet fibers held onto theunderside of the felt 26 as the wire 44 and the felt 26 pass togetherover the roller 48 with the webs formed on the respective surfaces incontacting relation one with the other.

By adjusting the vertical position of the roller 54 which` followsroller 48 and engages the upper wall of the felt 26, it has been foundpossible to achieve a clean and substantially complete transfer of thedry web 16 of fibers of reinforcing lengths from the wire 44 to the wetlayer 12 of pulp fibers without the necessity for wetting the wire 44.Thereafter, the felt 26 with the webs adhered to the underside thereofis passed successively overrone or more additional cylinders 22 in thevats 56 and 58. Provided that the web has not been made undesirablythick, the cylinders 22 in the subsequent vats 56and 58 and the likewill contribute additional wetl lamina to the underside of the felt toprovide a compositestructure consisting of the web 16 of fibers ofreinforcing lengths sandwiched between thecpaper stock lamina'. 12acquired from the Yat Sti-M0118"18'and'20`and'the'1amina 12"from the vatsections 56 and 58, as represented, by ltheenlarged'- sectional View inFigure 3 of the drawing. The compositestructure indicated by the numeral60 then passes in a conventional manner between the press rolls 62 and30, the baby presses 64, subsequent press rolls formed as of the rollers66 land 32, and thereafter into additional press sections and driers,The presses operate to squeeze out free water from the web 60 to compactit and to embody or encase the filaments of reinforcing lengths in thedry web 16 into the adjacent lamina 12 and 12"of the shorter paperfibers generally of the paper pulpl type. The compacted compositestructure indicated by `the numeral is then dried and finished byoperations whichv are substantially conventional in the various stepsdescribed upon leaving the final vats 56 and 58.

In the modification of Figure 2, use is made of a conventionalFourdrinier machine havinganendless wirev operating about rollers 72, 74, 76, 78 and 8f) with a'head box 82 on the lead-in end of the wirewhich supplies a continuous stream 34 of slurry S6 containing paper pulpfibers onto the wire for the separation of the fibers thereon to form aweb 86 as the water drains through. Along the wire another stream l8f?of paper pulp in a slurry is flowed onto the web 86 from a secondary/headbox 90 locatedl over a series of suction boxes 92 to deposit a facelamina 94 of paper stock onto the web, after which the composite web 96passes from thewire to between'the first press rolls 98 and 100 and thenthrough'subsequent press sections and driers, as employed in aconventional paper making7 machine of the Fourdrinier'type.

After the first web 86 'has been formed onv the wire 70 from the slurryof the first headbox S2 and prior to the' formation of the face lamina94 by the slurry from the second headbox 90, a dry web of fibers ofreinforcing lengths is applied to the web 86 for sandwiching betweenithe wet webs 86 and 94.

As illustrated in the drawing, the dry web of fibers of reinforcinglengths is formed on a wire 102 such as an endless wire which operatesabout rollers 104, 106 and 108 for passage as the collecting surfacebeneath a fiber depositing head 110 of the type previously described.`Fibers of the desired lengths and composition are introduced into thecylinder of the head 110 for entrainment in an air stream with which itcirculates about the housn ing for passage, in the described manner,through the openings in the bottom wall of the housing to theseparatingwall whereby the fibers are deposited on the surface of thescreen in interfelting relation to form a web 112 asthe air is drawnthrough the screen by the suction'box 114. When the amount of airwithdrawn by the suction box is greater by a slight amount than the airwhich passes with the fibers through the -separating wall of the fiberdepositing head 110, the area between the head and the screen may beleft open to the atmosphere; as illustrated, since the deficiency willbe made up by a slight iniiow of air from the surrounding atmosphere toprevent the fibers from being blown out into the room. The roller 108employed to bring the web 112 intoeontacting relationship With thewetweb 86 for coucliingthe dry web of fibers of reinforcing lengths ontothe deposited Wet web 86 -of fibers may be `situated immediately inadvance ofthe suction boxes 92 or within the suction box section, as onor beyond the first or second bo'x, and the pressure of the roller 103is so adjusted as to cause a clean transfer of the dry web 112 of fibersof reinforcing lengths which is deposited by the head Milon the wirey102. With the arrangement illustrated, a surface lamina 94 of paperstock is applied over the transferred dry web 112 by the secondary headbox 9i) and the sandwich so formed is pressed andy dried in the pressand drier vsections conventionally employed, as previously described. Ifdesired, the composite web 96 may be creped before rying by well knownmeans which need not here be described to provide arstructure such as isillustrated in Figure 6.of the drawing. e f

vA product'such asimaylbe formed accordance with this invention isillustrated in Figure 3 of the drawing where the web 16 or 112 cf thedry filaments .of sub? stantial length is laminated between the outerwet de-` may be incorporated in the finished web 60 by adding' other drydepositing systems of the typedescribed by the more than one pair ofvats 22.

In practicing the invention it has been found desirable to limit thethickness of the web of included dry fibers of reinforcing lengths toone that is thin enough to provide a sufficiency of openness between thedeposited filaments so as to enable the pulp fibers of the sandwiching.

lamina 12 or 86 and 12 or Y94 to come into mutual contact one with theother when the composite web is subsequently processedl as in thepresses and driers thereby at least partially to envelope the individualdry filaments of reinforcing lengths which are incorporatedtherebetween. The filaments or other fibers of reinforcing lengths whichare contemplated for use in the practice of this invention are, ingeneral, incapable of being bonded together by mere moistening andpressing but the filaments can be incorporated into the web in a bondedrelationship by encasement with the moistY paper pulp fibers in theadjacent lamina thereby to enable the entire laminated strength whensubsequently wetted or to impart other properties to the composite sheetor web, it is often desirable to embody a small amount of an adhesivesuch as animal glue, carboxymethyl cellulose, starch, or the like; or athermo-reactive resinous binder such as a urea-k formaldehyde resin, aphenol-aldehyde resin or a melamineformaldehyde resin for wet strengthor in the alternative, or in addition, to embody a sizing agent as anemulsion of wax or'rosin. The bonding materials and the sizingmaterials, when incorporated, may be applied in the form of asolution,or an emulsion or a suspension, as' by spraying the additive onto thedry web 16 or 112 formed of the fibers of reinforcing lengths during orafter its formation as by means of sprays 116 or 116 directed from sprayguns 118 onto the formed web immediately after formation and prior tocouching onto the wet lamina of paper fibers formed as by other systemsas described in my issued Patent No. 2,698,271. By lthis procedure ithasbeen found possible to incorporate the desired additive in the finalsheet in a manner which insures almost complete retention asdistinguished froml the` application of such additive by means of thestock or slurry employed for manufacture of the paper lamina, as in theusual practice. When such additives are applied in the paper stock, asubstantial portion of the additive is lost by drainage on the formingwire or else is squeezed out by the presses. Since the fibers ofreinforcing lengths are incorporated in the form of a'dry lamina andbecause the dry lamina is centered by sandwiching between the wet layersin the final structure, the additive is, for all practical purposes,believedl wholly to be retained on the fibers and in the web, especiallyif it is added in the form of a suspension or an emulsion wherein theliquid or dissolved additive has a high viscosity.

If vthe material added to the fibers in the manner'de scribed is capableof functioning as `a binder for the filaments, such for example as whenuse is made of a thermo-reactive resin, it is found possible to formthe' dry layer of bers of reinforcinglengths to any thickness which maybe desired since the dependency for strength and bonding by the use ofVthe outer layers of paper fibers from'the paperstock'is then minimized.However, when making a composite sheet with a thin lamina of fibers ofreinforcing lengths, the addition of a small quantity such as even afraction of 1 percent by weight of a suitable resin based upon theweight of the dry deposited web of fibers is often desirable since mostspecifications for reinforced papers are met more effectively by theaddition of coating materials to provide a substantial degree of wetstrength. Moreover, as has been pointed out, the beneficial effectsderived from the use of small quantities of resin added in the mannerdescribed are usually substantially greater in the system described thanthat which is made available from the use of the same amount of resinousmaterials added to papers made by processes which have heretofore beenemployed.

Various modifications may be embodied in the practice of this inventionto produce structures having different fiber arrangements yas byadjustment in the location of the position for couching or otherwisetransferring the dry web of reinforcing fibers onto the wet web of paperstock with respect to the elements by which the webs of paper stockfibers are formed. For example, in Figure 4 of the drawing, illustrationis made of a product having a paper stock layer, such as would be formedof the webs 12 or 86 with the webs 16 or 112 of fibers of reinforcinglengths on the surface thereof without an overlying layer of wet paperstock fibers. A structure of this character could be fabricated by theuse of the vats 18 and 20 in combination with the system for theformation and transfer of the dry web 16 of fibers of reinforcinglengths without the subsequent use of the vats 56 and 58 or else thestructure might be formed by omission of the second headbox 90 in thesystem illustrated in Figure 2 of the drawing.

While it is preferred to make application of a small amount of resinousbinder to the dry web of fibers of reinforcing lengths to improve thebonding relation with the paper stock fibers and to impart greater webstrength to the product, structures formed without such binder additionsare capable of many uses such as for conversion into a reinforcedmulti-ply sheet represented by Figure of the drawing. In the fabricationof a multi-ply sheet of the type described, a suitable potentiallaminant 120 formed of a material such as a water suspension of asphaltor microcrystalline wax or a solution or an emulsion of a resin islaminated between webs of the type illustrated in Figure 4 with the faceplies 16 or 112 of the fibers of reinforcing lengths in surface contactwith the laminant 120. Instead of making use of two plies of reinforcedwebs of fibers illustrated in Figure 4, use may be made of one of thereinforced plies on one side of the laminate with another ply 122 formedof an unreinforced web of fibers on the other side. If sufiicientasphalt or resin or other laminant is employed, it will function as abinder which substantially fills the interstices between the fibers inlamina 16 or 112 whereby a very thick layer of such fibers ofreinforcing lengths may be incorporated, if desired, in the structurewithout increasing the possibility for delamination.

While the preferred method of applying the randomly deposited filamentlamina as represented by the webs 16 or 112 has been disclosed to formthe composite sheet, it will be understood that the point or points ofapplication of such lamina or dry webs is not limited to the positionsdescribed. Instead, application, as previously indicated, can bedeferred until after the couching and at least part of the pressingoperations. For example, when a combined Fourdrinier machine and amultiple cylinder machine is employed, or when use is made of a pair ofduplexing Fourdrinier machines, it can be made more convenient to applythe dry web 16 or 112 or reinforcing fibers after the couching operationhas been completed and the wet web removed from the primary carrier orwire. However, for practical application, it is preferred to maintainthe outer plies of paper stock wet enough to cohere together whenpressed andprovision should be made to press the composite web rmlytogether before drying so that the sandwiching outer paper stock plieswill cohere to cause their fine fibers to envelope the individualfilaments of the dry web of fibers. If sufficient binder is added to thefilaments, the laminating operation may be deferred until thesandwiching webs are considerably drier but it is preferred to maintainat least one of the webs sufficiently moist for molding of the typewhich would cause displacement of the paper stock fibers to the spacebetween the filaments of the dry web of fibers substantially to envelopethe filaments in subsequent pressing operations.

Suitable filaments for use in the preparation of the reinforcing web arepreferably selected to have a length greater than A inch and preferablygreater than 556 inch` with the maximum length of fibers beingdetermined by that conveniently handled in a fiber depositing head ofthe type described. Efficient operation can be achieved with'fibershaving lengths as great as 2% to 3 inches. In practice, it is preferredto make use of reinforcing fibers or filaments having a length betweenl/ to 1V: inches unless a fiber depositing head of the type described inapplication Ser. No. 464,102 is employed where use can be made ofreinforcing filaments and fibers of greater lengths. The thickness ofthe filaments should not be so great as to impair the smoothness of theresulting composite sheet that is formed. However, especially ifadequate pressure is applied to the composite laminae before drying, thefilaments of fibers of reinforcing lengths may be almost as thick asthefinal dried and calendered sheet without being unduly prominent.

Upon examining a composite sheet prepared in accordance with thepractice of this invention, the filaments in the reinforcing lamina willbe found to be uniformly distributed and randomly oriented with respectto the faces of the sheet. Unless the reinforcing lamina is bound withan additive or'else comprises thermoplastic filaments, adequate spaceremains between the fibers of the filaments to permit the laminaadjacent to the filaments to envelope the fibers and cohere withsufficient strength to permit normal use of the composite sheet as apaper in the manufacture of bags and the like without noticeabledelami-A nation of the plies. When use is made of a web of reinforcingfibers as a thin layer in combination with webs of paper stock having athickness substantially greater than that of the reinforcing filaments,sufficient of the filaments will be present to cause an increase in tearstrength to at least percent of that and possibly several times thatavailable from the same weight of paper without the added filaments. Aproduct prepared in accordance with the practice of this invention canbe readily distinguished over paper stock in which similar filaments offibers of reinforcing lengths are incorporated with the pulp fiberssince such filaments will be located in admixture with the pulp fibersin the paper plies with the filaments more or less oriented with thedirection of movement of the wire whereas a product prepared inaccordance with the practice of this invention will be characterized bythe fact that the filaments lie in a particular lamina and are notoriented in the direction in which the sheet was made.

If a thick lamina of reinforcing filaments is incorporated in acomposite sheet in accordance with the practice of this invention,preferably with the addition of a binder or by the use of thermoplasticfibers as a bonding agent, the filaments in at least one face of thelamina will become imbedded in the adjacent lamina of paper stock whichwould be characteristic of the filaments having been applied to theadjacent lamina of the paper stock prior to pressing and drying, inaddition to the fact that the filaments will be uniformly distributedand randomly oriented in the reinforcing lamina.

For certain applications, such as in the fabrication of paper sacks orcase liners, it is desirable to crepe or crinkle the lpaper sheet eitherbefore or after drying so as to provide the sheet with sufiicientstretch4 to minimize breaking. A sheet of the type described isillustrated in Figure 6 of the drawing. Creping the sheet before dryingis preferred from the standpoint of economy and convenience over andabove the process for creping or crinkling subsequent to drying whichwould require a separate operation or special machines. For thispurpose, it is preferred to make use Vof an additional layer ofreinforcing fibers to compensate for the loss in strengths occasioned bythe more economical wet creping process described. The economy achievedby wet craping more than offsets the additional cost which might beinvolved in the Aapplication in use of additional lamina of reinforcingfibers.

It will be understood that various changes may be made in the details ofconstruction, arrangement and in products that are formed in accordancewith the practice of this invention without departing from the spirit ofthe invention, especially as defined in the following claims.

I claim:

1. The method of making a reinforced multiply paper comprising the stepsof moving an endless member continuously in one direction, depositing awet layer of paper pulp fibers as a continuous layer on the surface ofthe moving member, moving another foraminous member continuously in onedirection at a linear speed corresponding to that of the first memberand with a portion thereof passing in closely spaced relation and in thesame direction with a portion of the first moving member having the wetweb of pulp fibers on the surface thereof, passing a stream of aircontaining dry fibers of reinforcing lengths uniformly distributedtherein through the foraminous member to separate out dry fibers ofreinforcing lengths in uniform distribution on the surface thereof toform an endless web of dry fibers on the foraminous member, contactingthe web of wet pulp fibers with the web of dry reinforcing fibers as themoving member and foraminous member travel in the same directiontogether in closely spaced relation with each other whereby the web ofdry reinforcing fibers is pressed onto the web of wet pulp fibers and iscouched from the foraminous member onto the layer of web fibers to formthe top ply on the layer of wet pulp fibers, compressing the formedlayers for consolidation, and then drying the consolidated layers toform a paper.

2. The method as claimed in claim 1 which includes the additional stepof creping the consolidated web before drying.

3. The method as claimed in claim l which includes the additional stepof forming a wet layer of paper pulp fibers as a continuous web on thesurface of the web of dry reinforcing fibers couched onto the underlyinglayer of wet pulp fibers, compressing the layers to form a consolidatedstructure, and then drying the consolidated structure to form a paper.

4. The method as claimed in claim 1 in which the dry web of reinforcingfibers is formed of glass fibers having a length in the range of 1/2 to21/2 inches.

5. The method as claimed in claim 1 which includes the additional stepof applying a binder onto the web of dry fibers prior to their beingcouched onto the formed layer of wet pulp fibers on the first movingsurface.

References Cited in the file of this patent UNITED STATES PATENTS226,660 Hayward Apr. 20, 1880 1,336,404 Weiss Apr. 6, 1920 1,995,145Frost Mar. 19, 1935 2,286,942 Tuten June 16, 1942 2,327,713 Hunter Aug.24, 1943 2,418,706 Goyette Apr. 8, 1947 2,422,345 Easterberg June 17,1947 2,504,744 sproull Apr. 18, 1950 2,581,069 Bertolet Jan. l, 1952

1. THE METHOD OF MAKING A REINFORCED MULTIPLY PAPER COMPRISING THE STEPSOF MOVING AN ENDLESS MEMBER CONTINUOUSLY IN ONE DIRECTION, DEPOSITING AWET LAYER OF PAPER PULP FIBERS AS A CONTINUOUS LAYER ON THE SURFACE OFTHE MOVING MEMBER, MOVING ANOTHER FORAMINOUS MEMBER CONTINOUSLY IN ONEDIRECTION AT A LINEAR SPEED CORRESPONDING TO THAT OF THE FIRST MEMBERAND WITH A PORTION THEREOF PASSING IN CLOSELY SPACED RELATION AND IN THESAME DIRECTION WITH A PORTION OF THE FIRST MOVING MEMBER HAVING THE WETWEB OF PULP FIBERS ON THE SURFACE THEREOF, PASSING A STREAM OF AIRCONTAINING DRY FIBERS OF REINFORCING LENGTHS UNIFORMLY DISTRIBUTEDTHEREIN THROUGH THE FORAMINOUS MEMBER TO SEPARATE OUT DRY FIBERS OFREINFORCING LENGTHS IN UNIFORM DISTRIBUTION ON THE SURFACE THEREOF TOFORM AN ENDLESS WEB OF DRY FIBERS ON THE FORAMINOUS MEMBER, CONTACTINGTHE WEB OF WET PULP FIBERS WITH THE WEB OF DRY REINFORCING FIBERS AS THEMOVING MEMBER AND FORAMINOUS MEMBER TRAVEL IN THE SAME DIRECTIONTOGETHER IN CLOSELY SPACED RELATION WITH EACH OTHER WHEREBY THE WEB OFDRY REINFORCING FIBERS IS PRESSED ONTO THE WEB OF WET PULP FIBERS AND ISCOUCHED FROM THE FORAMINOUS MEMBER ONTO THE LAYER OF WEB FIBERS TO FORMTHE TOP PLY ON THE LAYER OF WET PULP FIBERS, COMPRESSING THE FORMEDLAYERS FOR CONSOLIDATION, AND THEN DRYING THE CONSOLIDATED LAYERS TOFORM A PAPER.